Precautions: 1) Do not apply external voltage to the voltage output, otherwise it will damage the fuel cell. 2) Store PEM fuel cells in a sealed container. 3) When connecting with the old pipe, make sure that all connecting parts and hoses are not leaking. 4) Do not disassemble the PEM media battery, otherwise it may cause damage to the ring. 3) Special damage indication: The positive and negative polarities on the EM water electrolyzer cannot be wrongly connected. Once the connection is wrong, the battery and the electrolyzer will be damaged or even unusable. ×Please read this carefully before using the instrument. The user will be responsible for the loss caused by the reverse connection of the electrode polarity and the battery fluid.